Nitrosyl trifluoride

ABSTRACT

COMPOUNDS OF FLUORINE, NITROGEN, AND OXYGEN, NAMELY, NITROSYL TRIFLUORIDE, FLUORYLDIFLUOROAMINE, NITRONIUMDIFLUORAMIDE, AND TETRAFLUORODINITROGEN OXIDE. THE COMPOUNDS ARE USEFUL AS OXIDIZERS IN ROCKET SYSTEMS.

United States Patent 3,554,699 NITROSYL TRIFLUORIDE John H. Gross, Lakeland, Fla., assignor to International Minerals & Chemical Corporation, a corporation of New York No Drawing. Filed Dec. 13, 1960, Ser. No. 75,488

Int. Cl. C01b 21/00 US. Cl. 23203 1 Claim ABSTRACT OF THE DISCLOSURE Compounds of fluorine, nitrogen, and oxygen, namely, nitrosyl trifluoride, fluoryldifluoroamine, nitroniumdifluoramide, and tetrafluorodinitrogen oxide. The compounds are useful as oxidizers in rocket propellant systems.

3,554,699 Patented Jan. 12, 1971 It is a specific object of the invention to provide the novel compounds nitrosyl trifluoride, NOF fluoryldifluoramine, F NOF, nitronium difluoramide, NO NF and tetrafluorodinitrogen oxide, (NF O.

Nitrosyl trifluoride .is prepared by reaction between nitrogen trifluoride and either ozonized oxygen or nitrous oxide in the presence of a glow discharge. Theoretically the reactions proceed as follows:

( a+ a" 3-l- 2 Temperatures of at least -1()0 C. and preferably from about 100 C. to about -200 C. are preferred when ozonized oxygen is employed. Pressure of at least about 0.1 mm. Hg, preferably from about one to about 600 mm.

' Hg, is employed.

pressure, and must be liquified at a very low temperature and handled as boiling liquids during loading and flight.

Compromise systems with lower performance have been used to avoid some of these practical difliculties.

Hydrogen-like fuels such as the hydrocarbons, am-

monia, and hydrazines, haveprovided significantly better density, handling, and storagecharacteristics than hydrogen, while retaining fairly good specific impulse with some oxidizers. However, no fluorine-based oxidizers are known to have been used, except perhaps in small experiments. Instead, other oxidizers have been substituted. Liquid oxygen, which seems to be the most effective oxidizer now in use, provides specific impulses five to fifteen percent lower than fluorine 'in a comparable systern. This sacrifice in performance does not actually give a major advantage in physical characteristics important properties of fluorine or oxygenbecome much more difficult. At the same time, the need to use an oxidizer giving very high energy release becomes imperative. It is, therefore, appropriate to seek an oxidizer which has better physical characteristics than either fluorine or oxygen, but retains oxidizing power approaching that of fluorine itself.

It is accordingly a primary object of this invention to provide novel oxidizers which are essentially compounds of fluorine, oxygen and nitrogen and which may be practically utilized in propellant systems to provide essentially all of the advantages which attend the use of oxygen or fluorine per se.

It is an additional primary object of the invention to provide novel compounds of fluorine, oxygen and nitrogen in combination with fuels requisite to provide complete rocket fuel systems.

Nitrogen trifluoride is preferably employed in at least stoichiometric quantities. Preferably the molar proportions of nitrogen trifluoride to oxygen containing reactant fall in the range of about 1:1 to about 5:1.

EXAMPLE I Nitrogen trifluoride, NF and oxygen are reacted at a temperature 163 C. and a pressure of 40 mm. Hg in the presence of a glow discharge. The partial pressure of NF in the system is maintained at about 20 mm. Hg, and the partial pressure of oxygen is allowed to fall until it has been largely consumed to form nitrosyl fluoride via intermediate conversion to ozone. Nitrosyl trifluoride condenses and .is isolated from the reaction products by conventional means such as distillation.

EXAMPLE II Nitrogen trifluoride and nitrous oxide in proportions stoichiometrically requisite to respond to the reaction indicated by Equation 2 are reacted in the presence of a glow discharge at a temperature of about -20 C. and a pressure of about 30 mm. Hg. The nitrosyl trifluoride, NOF is separated from the nitrogen byproducts by chilling the gas stream to about 14(l C.

A propellant system including nitrosyl trifluoride is appropriately formed from a combination of nitrosyl trifluoride and ammonia, there being present in such a system at least about 0.24 part by weight of the fuel for each part of oxidant.

Fluoryldifluoramine, 'F NOF, is prepared by the reaction in the presence of a glow discharge between tetrafluorohydrazine, N F and oxygen monofluoride, 0 1 in accordance with Equation 3.

The reaction is appropriately eflected at a temperature of from about 200 C. to about l00 C. and a pressure of from about 1 mm. Hg to about 500 mm. Hg. At least a stoichiometric amount of N F is utilized. Preferred proportions of reactants comprise a stoichiometric excess of N F of from about 10 to about 50 percent.

EXAMPLE 1n Liquid tetrafluorohydrazine is cooled to 135 C. in a vessel equipped with discharge electrodes in the vapor about 60 C., preferably at a temperature of from about 60 C. to about -130 C., but not colder than 150 C. In this alternative procedure a glow discharge is not required. The reaction may be indicated as shown by Equation 4. (4) F NH+OF F NOF+HF EXAMPLE IV In completing the reactions indicated by Equations 5, 6, 7, and 8, the nitrogen oxides are maintained in a condensed state in a suitable reaction vessel and tetrafluorohydrazine or nitrogen trifluoride is passed into the reaction vessel in the manner generally described in Example IV, the temperature being such as to maintain the nitrogen oxides in the liquid phase, that is to say at a temperature below 21 C. when N is utilized, or at a temperature below 32 C. when N 0 is utilized. Nitrosyl fluoride, NOF, is a by-product of all reactions.

EXAMPLE V N 0 is charged into a reaction vessel maintained at a temperature of about 0 C. Tetrafluorohydrazine, N F is passed into the liquid N 0 in the reaction vessel to provide nitroniumdifluoramide, NO NF as shown in Equation 5.

EXAMPLE VI Example V is repeated with the exception that nitrogentrifluoride, NF is utilized in lieu of tetrafluorohydrazine to provide nitroniumdifluoramide as shown in Equation 7.

EXAMPLE VII N 0 in the solid form is charged into a reaction vessel maintained at 0 C. Tetrafluorohydrazine is introduced into this reaction vessel to provide nitronium difluoramide as a reaction product in accordance with Equation 6.

EXAMPLE VIII Example VII is repeated with the exception that nitrogenfluoride, NF is utilized in lieu of tetrafluorohydrazine, N F to produce nitronium difluoramide in accordance with Equation 8.

Tetrafluorodinitrogen oxide (NF O is prepared by the reaction between tetrafluorohydrazine and nitrous oxide in accordance with Equation 9.

Nitrous oxide, N 0, and tetrafluorohydrazine are comingled at atmospheric pressure in the presence of a transition group catalyst, specifically platinum, at room temperature to provide tetrafiuorodinitrogen oxide as shown in Equation 9. The by-products produced include nitrogen trifluoride, NF and nitrosyl fluoride, NOF. The formation of by-products may be minimized by increasing the pressure. Preferably, the reaction is effected at a pressure from about 10 to about 50 pounds per square inch and a temperature of about 50 C. to about C. Catalysts other than platinum which may be used include palladium, nickel, and molybdenum.

Alternatively, tetrafluorodinitrogen oxide may be prepared by the reaction between difluorodiazine, FN=NF, and oxygen difluoride, 0P as shown in Equation 10.

The reaction is preferably effected at a temperature of not greater than 0., preferably at a temperature of from about C. to about -150 C., at a pressure of from about two to about 200 pounds per square inch. Excess difluorodiazine is preferably utilized.

EXAMPLE X Solid difluorodiazine, in excess of that stoichiometrically required by Equation 10, and liquid oxygen difluoride are reacted at a temperature of C. under a pressure of 5 atmospheres to provide (NF O as shown in Equation 10.

The following table is representative of propellant systems including the various compounds contemplated by the present application, with various fuels. The carbonaceous fuels shown are chosen to have a favorable composition, with respect to carbon-hydrogen ratio, when oxidized by the compounds shown opposite them. However, the propellant systems contemplated in this application are not restricted to those tabulated. The compounds contemplated are capable of energetic reaction with any fuel, the choice and proportion of fuel for each system being governed by consideration of flame temperature, average molecular weight of combustion products, and

density.

Table I Oxidizer: Fuel NOF3 Or NH3 NOF or F NOF N H NOF or F NOF (NH CH CH NH NO NF Alkanes NO NF NH 2)2 3)2 2 (NF O NH CH CH NH 2)2 2 4 I claim: 1. The compound, NOF

References Cited UNITED STATES PATENTS 2,972,519 2/1961 Lipscomb 23-205 2,428,331 9/ 1947 Hutchinson 23-205 2,930,684 3/1960 Kanarek 520.5 2,954,283 9/1960 Horvitz 520.5 3,032,400 5/1962 Marsh 23203 EDWARD J. MEROS, Primary Examiner U.S. Cl. X.R. 14936, 109 

